Project Summary Suppression of receptor tyrosine kinase (RTK)/Kras/Mitogen Activated Protein Kinase (MAPK) signaling pathway by sprouty (SPRY) proteins is a tumor suppressor mechanism in cancers of many tissues. Recent studies from the laboratory though demonstrated cancer promoting role of SPRY2 in colorectal cancer (CRC), its clinical and translational relevance in CRC progression, treatment, recurrence and survival is not known. Kras mutation is an early stage mutation in CRC. In Aim 1 requirement of SPRY2 in CRC progression will be assessed in genetically-engineered-mouse-models (GEMMs) by Cre-mediated embryonic activation of Kras allele at codon 12 (KrasLSL-G12D), embryonic deletion of SPRY2 (SPRY2fl/fl) and a double mutant with both activated Kras and deleted SPRY2 during azoxymethane (AOM)-induced colonic carcinogenesis. Studies will be extended to assess the effects of CRISPR/Cas9 editing of SPRY2 in isogenic Kras mutant and wild type isogenic cell lines and patient-derived-xenografts established from Kras mutant wild type tumors. Kras mutational status dictates the use of epidermal growth factor receptor inhibitors in metastatic CRC. Studies in Aim 2 will assess in vivo effects of Cetuximab treatment on CRISPR/Cas9 SPRY2 edited isogenic Ras mutant and wild type cells and the PDX cell lines established from CRC patients. SPRY2 expression in primary tumors may correlate directly with tumor recurrence and long-term survival. Studies in Aim 3 will determine whether SPRY2 expression in stage II-III primary tumors is predictive/prognostic for cancer recurrence and survival. For this analysis the cancer genome network (TCGA) that is linked to outcomes will be utilized.